Coated article with ir reflecting layer and method of making same

ABSTRACT

A coated article is provided with a low-emissivity (low-E) coating on a glass substrate. The low-E coating includes an infrared (IR) reflecting layer between at least a pair of dielectric layers. The IR reflecting layer may be of silver or the like. The coating is designed so as to provide a highly transparent coated article that is thermally stable upon optional heat treatment and which can be made to have a low emissivity in a consistent manner. The coating is designed to have improved IR reflecting layer quality, and thus reduced tolerances with respect to manufacturability of desired emissivity values. The coated article may be used in monolithic window applications, IG window applications, or the like.

This invention relates to a coated article having a low-emissivity(low-E) coating including an infrared (IR) reflecting layer of orincluding a material such as silver or the like. The low-E coating isdesigned so that the coated article can realize one or more of: highvisible transmission, consistent and low emissivity values, thermalstability upon optional heat treatment such as thermal tempering, a lowU-value, and desirable coloration and/or reflectivity values. Coatedarticles herein may be used in the context of insulating glass (IG)window units, or in other suitable applications such as monolithicwindow applications, laminated windows, and/or the like.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Coated articles are known in the art for use in window applications suchas insulating glass (IG) window units, vehicle windows, monolithicwindows, and/or the like. In certain example instances, designers ofcoated articles often strive for a combination of high visibletransmission, desirable color, low emissivity (or emittance), low sheetresistance (Rs), and/or low U-values in the context of IG window units.High visible transmission and desired coloration may permit coatedarticles to be used in applications where these characteristics aredesired such as in IG or vehicle window applications, whereas lowemissivity and low sheet resistance permit such coated articles to blocksignificant amounts of IR radiation so as to reduce for exampleundesirable heating of vehicle or building interiors.

Low-E coatings are typically deposited on a glass substrate bysputtering. Emissivity and/or sheet resistance values of a coating orcoated article are driven in large part by the IR reflecting layer(s)which is/are typically made of silver or the like. However, it has beendifficult to achieve low tolerance variation with respect to emissivityvalues of such coatings. In other words, a problem in the art has beendifficulty in achieving a desired low emissivity value and/or sheetresistance value within a given small tolerance variation. The tolerancevariation has been larger than desired.

In view of the above, it will be appreciated that there exists a need inthe art for a coated article including a low-E coating that is designedso that a desired low emissivity value can be achieved within a givensmall tolerance range (e.g., a tolerance of plus/minus 1%). It wouldalso be desirable to provide such a coating that also achieves one ormore of: high visible transmission, low emissivity, thermal stabilityupon optional heat treatment such as thermal tempering, a low U-value,and desirable coloration and/or reflectivity values.

In certain example embodiments of this invention, it has surprisinglybeen found that the provision of a layer of or including zirconiumsilicon oxynitride in the lower dielectric portion of the coating,between the glass substrate and the IR reflecting layer (e.g., of silveror the like) unexpectedly improves the quality of the IR reflectinglayer thereby permitting the coated article to realized low emissivityvalues with low tolerance variations. Providing zirconium siliconoxynitride under a layer of or including zinc stannate and under a layerof or including zinc oxide, in the lower dielectric portion of thecoating, has surprisingly been found to improve the quality of thesilver and thus lower emissivity values and lower emissivity tolerancevalues in a desirable manner. Even though the zirconium siliconoxynitride is not directly contacting the IR reflecting layer, it stillsurprisingly improves the quality of the overlying IR reflecting layerthereby permitting thermal properties of the coating to be improved andmanufactured in a more consistent manner. The IR reflecting layer hasbeen found to grow better and have a smoother base which can more easilybe repeated on a consistent basis. It has also been surprisingly foundthat the provision of a layer of or including titanium oxide (e.g.,TiO₂) over the zirconium silicon oxynitride unexpectedly results in anincrease in visible transmission of the coated article and improvedoptical properties, as well as an increase in line speed.

In certain example embodiments of this invention, there is provided acoated article including a coating supported by a glass substrate, thecoating comprising moving away from the glass substrate: a dielectriclayer comprising zirconium silicon oxynitride; a layer comprisingtitanium oxide; a layer comprising zinc stannate; a layer comprisingzinc oxide located over and directly contacting the layer comprisingzinc stannate; an infrared (IR) reflecting layer comprising silverlocated on the substrate over and directly contacting the layercomprising zinc oxide; and a layer comprising metal oxide located overat least the IR reflecting layer comprising silver; wherein the coatingcontains only one silver based IR reflecting layer; wherein the coatinghas a normal emissivity (E_(n)) of no greater than 7%, and measuredmonolithically the coated article has a visible transmission of at least75%.

In certain example embodiments of this invention there is provided acoated article including a coating supported by a glass substrate, thecoating comprising moving away from the glass substrate: a dielectriclayer comprising zirconium silicon oxynitride; a layer comprising zincstannate; a layer comprising zinc oxide located over and directlycontacting the layer comprising zinc stannate; an infrared (IR)reflecting layer comprising silver located on the substrate over anddirectly contacting the layer comprising zinc oxide; and a layercomprising metal oxide located over at least the IR reflecting layercomprising silver; wherein the layer comprising zirconium siliconoxynitride contains at least three times as much nitrogen as oxygen, andwherein a ratio of Zr/Si (atomic) is from 0.30 to 0.47 in the layercomprising zirconium silicon oxynitride.

In certain example embodiments of this invention, there is provided anIG window unit comprising: first and second glass substrates with a gaptherebetween; a coating supported by the second glass substrate andfacing the gap, the second glass substrate to be located closer to abuilding interior than is the first glass substrate, the coatingcomprising moving away from the second glass substrate: a dielectriclayer comprising zirconium silicon oxynitride; a layer comprisingtitanium oxide; a layer comprising zinc stannate; a layer comprisingzinc oxide located over and directly contacting the layer comprisingzinc stannate; an infrared (IR) reflecting layer comprising silverlocated on the substrate over and directly contacting the layercomprising zinc oxide; and a layer comprising metal oxide located overat least the IR reflecting layer comprising silver; wherein the coatingcontains only one silver based IR reflecting layer; wherein the coatinghas a normal emissivity (E_(n)) of no greater than 7%; wherein the IGwindow unit has a visible transmission of at least 70% and a U-value ofno greater than 1.4.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a coated article according to anexample embodiment of this invention.

FIG. 2 is a cross sectional view of a coated article according toanother example embodiment of this invention.

FIG. 3 is a cross sectional view of part of an insulating glass (IG)window unit including the monolithic coated article of FIG. 1 or FIG. 2according to an example embodiment of this invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Referring now to the drawings in which like reference numerals indicatelike parts throughout the several views.

Coated articles herein may be used in applications such as monolithicwindows, IG window units that include a monolithic coated article,vehicle windows, and/or any other suitable application that includessingle or multiple substrates such as glass substrates.

Certain embodiments of this invention relate to a coated article havinga low-emissivity (low-E) coating supported by a glass substrate, thelow-E coating including an infrared (IR) reflecting layer of orincluding silver or the like. The low-E coating is designed so that thecoated article can realize one or more of: high visible transmission,consistent and low emissivity values, thermal stability upon optionalheat treatment such as thermal tempering, a low U-value, and desirablecoloration and/or reflectivity values.

In certain example embodiments of this invention, it has surprisinglybeen found that the provision of a layer of or including zirconiumsilicon oxynitride 2 in the lower dielectric portion of the coating 25,between the glass substrate 1 and the IR reflecting layer (e.g., ofsilver or the like) 9 unexpectedly improves the quality of the IRreflecting layer 9 thereby permitting the coated article to realized lowemissivity values with low tolerance variations. In particular,providing zirconium silicon oxynitride 2 under a layer of or includingzinc stannate (5 and/or 5′) and under a layer of or including zinc oxide(7 and/or 7′), in the lower dielectric portion of the coating 25, hassurprisingly been found to improve the quality of the silver and thusimprove (lower) emissivity and lower emissivity tolerance values asdiscussed herein. Even though the zirconium silicon oxynitride 2 is notdirectly contacting the IR reflecting layer 9, it still surprisinglyimproves the quality of the overlying IR reflecting layer 9 therebypermitting thermal properties of the coating to be improved andmanufactured in a more consistent manner. The IR reflecting layer 9 hasbeen found to grow better and have a smoother base which can more easilybe repeated on a consistent basis. It has also been surprisingly foundthat the provision of a layer of or including titanium oxide (e.g.,TiO₂) 3 over the zirconium silicon oxynitride 2 unexpectedly results inan increase in visible transmission of the coated article and improvedoptical properties, as well as an increase in line speed.

The terms “heat treatment” and “heat treating” as used herein meanheating the article to a temperature sufficient to achieve thermaltempering, heat bending, and/or heat strengthening of the glassinclusive article. This definition includes, for example, heating acoated article in an oven or furnace at a temperature of least about 580degrees C., more preferably at least about 600 degrees C., for asufficient period to allow tempering, bending, and/or heatstrengthening. In certain instances, the HT may be for at least about 4or 5 minutes. The coated article may or may not be heat treated indifferent embodiments of this invention.

FIG. 1 is a cross sectional view of a coated article according to anexample embodiment of this invention. The coated article includes glasssubstrate 1 (e.g., clear, green, bronze, or blue-green glass substratefrom about 1.0 to 10.0 mm thick, more preferably from about 1.0 mm to6.0 mm thick, with an example glass substrate being a clear glasssubstrate about 3.8 to 4.0 mm thick), and a multi-layer low-E coating(or layer system) 25 provided on the substrate 1 either directly orindirectly. As shown in FIG. 1, the coating 25 includes: dielectriclayer of or including zirconium silicon oxynitride 2, dielectric layerof or including titanium oxide (e.g., TiO₂) 3, dielectric layers 5 and5′ of or including zinc stannate, dielectric layers 7 and 7′ of orincluding zinc oxide, IR reflecting layer 9 of or including silver,gold, or the like, upper contact layer 11 of or including Ni, Cr, NiCr,NiCrMo, or any oxide thereof such as an oxide of NiCr or an oxide ofNiCrMo, dielectric layer 12 of or including a metal oxide such as zincstannate or the like, dielectric layer 13 of or including a metal oxidesuch as zinc oxide or the like, dielectric layer 14 of or including ametal oxide such as tin oxide (e.g., SnO₂), zinc stannate, or the like,dielectric layer 15 of or including a material such as silicon nitride(e.g., Si₃N₄) and/or silicon oxynitride, and an optional dielectriclayer 16 of a material such as zirconium oxide (e.g., ZrO₂) which may incertain example instances be a protective overcoat. Other layers and/ormaterials may additionally be provided in certain example embodiments ofthis invention, and it is also possible that certain layers may beremoved or split in certain example instances. For example, optionally alayer of or including silicon nitride and/or silicon oxynitride (notshown) may be provided between the glass substrate 1 and the zirconiumsilicon oxynitride 2. Moreover, other materials may be used forparticular layers instead of the materials mentioned above in certainexample embodiments of this invention.

FIG. 2 is a cross sectional view of a coated article according toanother example embodiment of this invention. The FIG. 2 embodiment hasthe same layer stack as the FIG. 1 embodiment, except that layers 5′, 7′and 14 from FIG. 1 are not present in the FIG. 2 embodiment. In the FIG.2 embodiment, the silver-based IR reflecting layer may be thicker thanin the FIG. 1 embodiment in certain instances so as to result in acoated article have a lower emissivity, lower sheet resistance, andlower U-value. It is also possible for silicon nitride inclusive layer15 to be thicker in the FIG. 2 embodiment, compared to the FIG. 1embodiment, to make up for the lack of layer 14 in the FIG. 2embodiment. These example modifications are reflected in examplesdiscussed below.

In monolithic instances, the coated article includes only one substratesuch as glass substrate 1 (see FIGS. 1-2). However, monolithic coatedarticles herein may be used in devices such as IG window units forexample. Typically, as shown in FIG. 3, an IG window unit may includetwo spaced apart glass substrates 1 and 22, with a gap 4 definedtherebetween. Example IG window units are illustrated and described, forexample, in U.S. Pat. Nos. 5,770,321, 5,800,933, 6,524,714, 6,541,084and US 2003/0150711, the disclosures of which are all herebyincorporated herein by reference. An example IG window unit as shown inFIG. 3 may include, for example, the coated glass substrate 1 shown ineither FIG. 1 or FIG. 2 coupled to another glass substrate 22 viaspacer(s), sealant(s) or the like with a gap 4 being definedtherebetween. This gap 4 between the substrates in IG unit embodimentsmay in certain instances be filled with a gas such as argon (Ar), or amixture of air and argon gas. An example IG unit may comprise a pair ofspaced apart substantially clear glass substrates each about 4 mm (e.g.,3.8 mm) thick one of which is coated with a coating 25 herein in certainexample instances, where the gap 4 between the substrates may be fromabout 5 to 30 mm, more preferably from about 10 to 20 mm, and mostpreferably about 16 mm. In certain example instances, the coating 25 maybe provided on the side of the inner glass substrate 1 facing the gap(although the coating may be on the other substrate in certainalternative embodiments) as shown in FIG. 3, which is often referred toas surface three of the IG window unit.

In certain example IG unit embodiments of this invention, the coating 25is designed such that the resulting IG unit (e.g., with, for referencepurposes, a pair of 3.8 mm clear glass substrates 1, 22 spaced apart by16 mm with a mixture of air and Ar gas in the gap) has a U-value of nogreater than 1.4 W/(m²K), more preferably no greater than 1.3 W/(m²K),sometimes no greater than 1.1 W/(m²K), and sometimes no greater than 1.0W/(m²K). U-value herein is measured and referred to in accordance withEN 410-673_2011—Winter, the disclosure of which is hereby incorporatedherein by reference. Indeed, it is preferred that the optical andthermal features discussed herein are achieved when the coating 25contains only one silver-based IR reflecting layer (e.g., as shown inFIGS. 1-2), as opposed to a double or triple-silver layer stack.

As mentioned above, it has surprisingly been found that the provision ofa layer of or including zirconium silicon oxynitride 2, in combinationwith the zinc stannate and zinc oxide, in the lower dielectric portionof the coating 25, between the glass substrate 1 and the IR reflectinglayer (e.g., of silver or the like) 9 unexpectedly improves the qualityof the IR reflecting layer 9 thereby permitting the coated article torealized low emissivity values with lower tolerance variations. Forexample, a low emssivity value (e.g., 4%) with a plus/minus 1% tolerancecan be surprisingly achieved using zirconium silicon oxynitride 2 incombination with the zinc stannate (5 and/or 5′) and zinc oxide (7and/or 7′) between the glass substrate 1 and the IR reflecting layer;but emissivity within the 1% tolerance cannot be achieved without usingthis combination of layers. This is a surprisingly and unexpectedimprovement in the art. Even though the zirconium silicon oxynitride 2is not directly contacting the IR reflecting layer 9, it stillsurprisingly improves the quality of the overlying IR reflecting layer 9thereby permitting thermal properties of the coating to be improved andmanufactured in a more consistent manner.

The nitrogen/oxygen ratio in the zirconium silicon oxynitride layer 2has been found to be significant. In particular, too much oxygen inzirconium silicon oxynitride layer 2 results in a reduced sputter rateand does not seem to help reduce absorption or increase transmissions.Too much oxygen in this layer 2 has also been found to result inundesirable haze. Accordingly, in certain example embodiments of thisinvention, the layer 2 of or including zirconium silicon oxynitride hasa nitrogen to oxygen ratio (nitrogen/oxygen ratio) of at least 3, morepreferably at least 4, and even more preferably at least 5 (atomic).Thus, layer 2 contains at least three times more N than O, morepreferably at least four times as much N than O, and most preferably atleast five times as much N than O. For example in certain exampleembodiments of this invention, layer 2 is sputter-deposited using a ZrSitarget, using from about 0.4 to 2.0, more preferably from about 0.5 to1.5, and most preferably about 0.8 to 1.0 ml/kW O₂ gas, and from about4.0 to 10.0, more preferably from about 5.0 to 8.0, and most preferablyfrom about 6.0 to 7.0 ml/kW N₂ gas. Argon (Ar) gas may also be used inthe sputtering process.

Moreover, it has also been found that, in zirconium silicon oxynitridelayer 2, too much Zr results in an undesirably brittle material and toolittle Zr causes the silver layer 9 to be not as smooth and degradescoating qualities. It has been found that better results in theserespects are achieved when the layer 2 contains more Si than Zr (atomic%). For example, the Zr/Si (atomic) ratio in layer 2 (and in thesputtering target for depositing layer 2) is preferably from 0.20 to0.60, more preferably from 0.30 to 0.47, and most preferably from 0.35to 0.44. For example, a sputtering target(s) containing about 40% Zr andabout 60% Si may be used to sputter-deposit layer 2.

Dielectric layer 3 may be of or include titanium oxide in certainexample embodiments of this invention. The titanium oxide of layer 3 mayin certain example instances be represented by TiO_(x), where x is from1.5 to 2.5, most preferably about 2.0. The titanium oxide may bedeposited via sputtering or the like in different embodiments. Incertain example instances, dielectric layer 3 may have an index ofrefraction (n), at 550 nm, of at least 2.0, more preferably of at least2.1, and possibly from about 2.3 to 2.6 when the layer is of or includestitanium oxide. In certain embodiments of this invention, the thicknessof titanium oxide inclusive layer 3 is controlled so as to allow a*and/or b* color values (e.g., transmissive, film side reflective, and/orglass side reflective) to be fairly neutral (i.e., close to zero) and/ordesirable. Other materials may be used in addition to or instead oftitanium oxide in certain example instances. In certain alternativeembodiments, the Ti in oxide layer 3 may be replaced with another metal.

In example embodiments, the dielectric zinc stannate (e.g., ZnSnO,Zn₂SnO₄, or the like) based layers 5, 5′ and/or 12 may include more Znthan Sn by weight. For example, the metal content of one or more ofthese zinc stannate based layers may include from about 51-90% Zn andfrom about 10-49% Sn, more preferably from about 51-70% Zn and fromabout 30-49% Sn, with an example being about 52% Zn and about 48% Sn(weight %, in addition to the oxygen in the layer) in certain exampleembodiments of this invention. Thus, for example, the zinc stannatebased layers may be sputter-deposited using a metal target comprisingabout 52% Zn and about 48% Sn in certain example embodiments of thisinvention. Optionally, the zinc stannate based layer 14 may be dopedwith other metals such as Al or the like. In certain optionalembodiments, it is possible to dope the zinc stannate (e.g., ZnSnO) withother materials such as Al, Zn, N, or the like. The zinc stannate basedlayers are substantially or substantially fully oxided in preferredembodiments of this invention.

Layers 7, 7′, and 13 in certain embodiments of this invention are of orinclude zinc oxide (e.g., ZnO). The zinc oxide of these layers maycontain other materials as well such as Al (e.g., to form ZnAlO_(x)).For example, in certain example embodiments of this invention, one ormore of zinc oxide layers 7, 7′, 13 may be doped with from about 1 to10% Al, more preferably from about 1 to 5% Al, and most preferably about1 to 4% Al. The zinc oxide layer(s) 7 and/or 7′, in combination with thezinc stannate (5 and/or 5′) and zirconium silicon oxynitride 2, helpsimprove silver quality of layer 9 and emissivity characteristics of thecoating 25 as explained herein.

Dielectric layer 15 may be of or include silicon nitride in certainembodiments of this invention. Silicon nitride layer 15 may, among otherthings, improve heat-treatability of the coated articles, e.g., such asthermal tempering or the like, and may or may not include some oxygen.The silicon nitride of layer 15 may be of the stoichiometric type (i.e.,Si₃N₄), or alternatively of the Si-rich type in different embodiments ofthis invention.

Infrared (IR) reflecting layer 9 is preferably substantially or entirelymetallic and/or conductive, and may comprise or consist essentially ofsilver (Ag), gold, or any other suitable IR reflecting material. IRreflecting layer 9 helps allow the coating to have low-E and/or goodsolar control characteristics. The IR reflecting layers may, however, beslightly oxidized in certain embodiments of this invention and mayoptionally be doped with other material such as Pd or the like. Coating25 preferably contains only one silver-based IR reflecting layer 9 inpreferred embodiments of this invention.

The upper contact layer 11 may be of or include nickel (Ni) oxide,chromium/chrome (Cr) oxide, or a nickel alloy oxide such as nickelchrome oxide (NiCrO_(x)), or other suitable material(s) such as Ni, Tior an oxide of Ti, or NiTiO_(x), in certain example embodiments of thisinvention. The use of, for example, NiCrO_(x) in these layers allowsdurability to be improved. The NiCrO_(x) of these layers may be fullyoxidized in certain embodiments of this invention (i.e., fullystoichiometric), or alternatively may only be partially oxidized (i.e.,sub-oxide). In certain instances, the NiCrO_(x) layer 11 may be at leastabout 50% oxidized. Descriptions of various types of oxidation gradedcontact layers that may optionally be used are set forth in U.S. Pat.No. 6,576,349, the disclosure of which is hereby incorporated herein byreference. Contact layer 11 may or may not be continuous in differentembodiments of this invention across the entire underlying IR reflectinglayer 9.

Transparent dielectric layer 14 may be of or include tin oxide incertain example embodiments of this invention. However, it may be dopedwith certain other materials in other example embodiments, such as withAl or Zn in certain example alternative embodiments.

Optionally, a protective overcoat layer such as zirconium oxide (e.g.,ZrO₂) may be provided as layer 16 as the uppermost layer of the coating25. This layer need not be provided in all embodiments. Protectiveovercoat 16 may instead be made of zirconium silicon oxynitride orsilicon oxynitride in alternative embodiments of this invention.

Other layer(s) below or above the illustrated coating may also beprovided. Thus, while the layer system or coating is “on” or “supportedby” substrate 1 (directly or indirectly), other layer(s) may be providedtherebetween. Thus, for example, the coating of FIG. 1 or FIG. 2 may beconsidered “on” and “supported by” the substrate 1 even if otherlayer(s) are provided between layer 2 and substrate 1. Moreover, certainlayers of the illustrated coating may be removed in certain embodiments,while others may be added between the various layers or the variouslayer(s) may be split with other layer(s) added between the splitsections in other embodiments of this invention without departing fromthe overall spirit of certain embodiments of this invention.

While various thicknesses may be used in different embodiments of thisinvention, example thicknesses and materials for the respective layerson the glass substrate 1 in the FIG. 1 embodiment are as follows, fromthe glass substrate 1 outwardly (e.g., the Al content in the zinc oxidelayers may be from about 1-10%, more preferably from about 1-3% incertain example instances):

TABLE 1 (Example Materials/Thicknesses; FIG. 1 Embodiment) More ExampleLayer Preferred Range ({acute over (Å)}) Preferred ({acute over (Å)})(Å) ZrSiO_(x)N_(y) (layer 2) 40-250 (or 20-250) Å  50-100 Å 74 Å TiO_(x)(layer 3) 15-150 {acute over (Å)} 20-60 {acute over (Å)} 30 Å ZnSnO(layer 5) 20-150 Å 35-70 Å 53 Å ZnAlO_(x) (layer 7′) 20-150 {acute over(Å)} 30-70 {acute over (Å)} 48 Å ZnSnO (layer 5′) 15-150 Å 25-60 Å 41 ÅZnAlO_(x) (layer 7) 60-170 {acute over (Å)}  80-140 {acute over (Å)} 123Å  Ag (layer 9) 50-120 {acute over (Å)}  70-100 {acute over (Å)} 87 ÅNiCrO_(x) (layer 11) 10-80 {acute over (Å)}  20-70 {acute over (Å)} 30 ÅZnSnO (layer 12) 30-130 Å 50-80 Å 66 Å ZnAlO_(x) (layer 13) 80-250{acute over (Å)} 130-240 {acute over (Å)} 170 Å  SnO₂ (layer 14) 15-150Å 30-80 Å 55 Å Si₃N₄ (layer 15) 50-350 {acute over (Å)}  80-200 {acuteover (Å)} 111 Å  ZrO₂ (layer 16) 10-60 Å  20-40 Å 30 Å

Turning to the FIG. 2 embodiment, while various thicknesses may be usedin different embodiments of this invention, example thicknesses andmaterials for the respective layers on the glass substrate 1 in the FIG.2 embodiment are as follows, from the glass substrate 1 outwardly (e.g.,the Al content in the zinc oxide layers may be from about 1-10%, morepreferably from about 1-3% in certain example instances):

TABLE 2 (Example Materials/Thicknesses; FIG. 2 Embodiment) PreferredMore Layer Range ({acute over (Å)}) Preferred ({acute over (Å)}) Example(Å) ZrSiO_(x)N_(y) (layer 2) 40-250  50-100 Å 74 Å (or 20-250) Å TiO_(x)(layer 3) 15-150 {acute over (Å)} 20-60 {acute over (Å)} 36 Å ZnSnO(layer 5) 10-150 Å 15-55 Å 22 Å or 31 Å ZnAlO_(x) (layer 7) 60-170{acute over (Å)}  80-140 {acute over (Å)} 73 Å or 88 Å Ag (layer 9)50-250 {acute over (Å)} 100-220 {acute over (Å)} 115 Å or 196 ÅNiCrO_(x) (layer 11) 10-80 {acute over (Å)}  20-70 {acute over (Å)} 30 ÅZnSnO (layer 12) 30-130 Å 50-80 Å 58 Å or 64 Å ZnAlO_(x) (layer 13)80-250 {acute over (Å)} 130-240 {acute over (Å)} 179 Å  Si₃N₄ (layer 15)50-350 {acute over (Å)}  80-200 {acute over (Å)} 146 Å or 189 Å ZrO₂(layer 16) 10-60 Å  20-40 Å 33 Å

In certain example embodiments of this invention, coated articlesaccording to the FIG. 1 and/or FIG. 2 embodiments herein may have thefollowing characteristics set forth in Table 3 when measuredmonolithically or in an IG window unit, and these values refer to bothheat treated and non-heat treated embodiments. Note that E_(n) is normalemissivity/emittance.

TABLE 3 Low-E/Solar Characteristics (HT or non-HT) CharacteristicGeneral More Preferred Most Preferred R_(s) (ohms/sq.): <=8.0 <=7.0<=5.0 E_(n): <=7% <=6% <=5% or <=4%

Moreover, coated articles including coatings according to the FIG. 1 andFIG. 2 embodiments of this invention have the followingoptical/color/thermal stability characteristics (e.g., when thecoating(s) is provided on a clear soda lime silica glass substrate 1from 1 to 10 mm thick, preferably about 4 mm thick such as 3.8 mmthick), as shown in Table 4 below. In Table 4, all parameters aremeasured monolithically. Note that “f” stands for film side, and “g”stands for glass side. Thus, R_(f)Y is film side reflectance, which isvisible reflectance measured form the film side of the coated substrate.And R_(g)Y is glass side reflectance, which is visible reflectancemeasured form the glass side of the coated substrate. Film sidereflectance, and film side reflective color values a*_(f) and b*_(f) aretypically deemed to be the most important when the coating 25 isprovided on surface three of an IG window unit because this indicateshow the outside of the building will appear. Note that ΔE* is a valueindicative of thermal stability, and in particular how much the opticalcharacteristics changes upon heat treatment (HT). The lower a ΔE* value,the less the applicable a*, b* and L* values change upon HT (e.g.,thermal tempering). The low ΔE* values of the coatings discussed hereindemonstrate that HT and non-HT versions of each coating substantiallymatching with respect to coloration. Note that the equation fordetermining ΔE* is known in the art and is described for example in U.S.Pat. No. 8,263,227, the disclosure of which is hereby incorporatedherein by reference. It has surprisingly been found that the combinationof the zinc stannate, zinc oxide, and zirconium silicon oxynitride inthe lower dielectric stack reduces ΔE* values in a desirable mannermaking the coatings more thermally stable.

TABLE 4 Example Optical Characteristics (Monolithic, HT or non-HT)Characteristic General More Preferred T_(vis) (or TY)(Ill. C., 2deg.): >=75% >=80% or >=86% a*_(t) (Ill. C., 2°): −5.0 to +1.0 −3.0 to0.0   b*_(t) (Ill. C., 2°): −2.0 to +6.0   0.0 to +4.0 R_(f)Y (Ill. C.,2 deg.): <=18% <=8% or <=6% a*_(f) (Ill. C., 2°): −5.0 to +8.0 −2.0 to+3.0 b*_(f) (Ill. C., 2°): −14.0 to +10.0 −11.0 to +1.0  ΔE*_(f): <=4.0or <=2.0 <=1.5 R_(g)Y (Ill. C., 2 deg.): <=20% <=8% a*_(g) (Ill. C.,2°): −5.0 to +5.0 −2.0 to +3.0 b*_(g) (Ill. C., 2°): −15.0 to +10.0−11.0 to 0     ΔE*_(g): <=2.5 or <=2.0 <=1.5

Moreover, coated articles including coatings according to the FIG. 1 andFIG. 2 embodiments have the following optical characteristics when thecoated article is provided in an IG window unit in certain exampleembodiments (see Table 5 below). These measurements are with respect to,for example and for purposes of reference, coating 25 being provided inan IG window unit where both glass substrates 1, 22 are clear soda limesilica glass substrates about 3.8 mm thick, coating 25 is on surfacethree of the IG unit as shown in FIG. 3, and when the gap between thesubstrates is about 16 mm thick and is filled with a mixture of air andargon gas. Note that U-value is measured and referred to in accordancewith EN 410-673_2011—Winter.

TABLE 5 Example Optical Characteristics (IG Unit; HT or non-HT)Characteristic General More Preferred T_(vis) (or TY)(Ill. C., 2deg.): >=68% or >=70% >=78% or >=79% a*_(t) (Ill. C., 2°): −5.0 to +1.0−3.0 to 0.0   b*_(t) (Ill. C., 2°): −2.0 to +6.0   0.0 to +4.0R_(outside)Y (Ill. C., 2 deg.): <=25% <=14% a*_(outside) (Ill. C., 2°):−5.0 to +8.0 −2.0 to +3.0 b*_(outside) (Ill. C., 2°): −10.0 to +10.0−7.0 to +4.0 R_(interior)Y (Ill. C., 2 deg.): <=25% <=14% a*_(interior)(Ill. C., 2°): −5.0 to +5.0 −2.0 to +3.0 b*_(interior) (Ill. C., 2°):−12.0 to +10.0 −7.0 to 0     U-value (W/(m²K)): <=1.4 or <=1.3 <=1.1 or<=1.0

EXAMPLES

Examples 1-8 are provided for purposes of example only, and are notintended to be limiting. The following Examples 1-8 were made viasputtering to have the layers set forth below from the clear glasssubstrate 1 outwardly. They were measured monolithically, heat treatedand then measured again. They were also put into IG window units asshown in FIG. 3. The silicon nitride layers were deposited by sputteringa silicon target (doped with about 8% Al) in an atmosphere includingargon and nitrogen gas. Layer thicknesses below in Table 6 are in unitsof angstroms (Å).

TABLE 6 Layer Stacks of Examples Layer Examples 1-4 Example 5 Examples6-8 ZrSiO_(x)N_(y) (layer 2) 74 Å 74 Å 74 Å TiO_(x) (layer 3) 30 Å 36 Å36 Å ZnSnO (layer 5) 53 Å 31 Å 22 Å ZnAlO_(x) (layer 7′) 48 Å n/a n/aZnSnO (layer 5′) 41 Å n/a n/a ZnAlO_(x) (layer 7) 123 Å  88 Å 73 Å Ag(layer 9) 87 Å 115 Å  196 Å  NiCrO_(x) (layer 11) 30 Å 30 Å 30 Å ZnSnO(layer 12) 66 Å 64 Å 58 Å ZnAlO_(x) (layer 13) 170 Å  179 Å  179 Å  SnO₂(layer 14) 55 Å n/a n/a Si₃N₄ (layer 15) 111 Å  146 Å  189 Å  ZrO₂(layer 16) 30 Å 33 Å 33 Å

Measured monolithically before tempering (HT), Examples 1-8 had thefollowing characteristics (annealed and non-HT, monolithic) (Ill. C, 2degree observer).

TABLE 7 Monolithic, annealed (before tempering) Ex. 1 Ex. 2 Ex. 3 Ex. 4Ex. 5 Ex. 6 Ex. 7 Ex. 8 T_(vis) (or TY):  88%  88%  88% 88%  87%  77%76% 75% a*_(t): −1.5 −1.4 −1.4 −1.5 −2.0 −3.2 −3.5 −3.2 b*_(t): 2.6 2.42.5 2.6 3.9 5.2 5.2 5.2 R_(f)Y:   5%   5%   5% 5% 5% 15% 16% 16% a*_(f):0.2 −0.5 −0.2 −0.5 1.8 5.1 5.6 4.7 b*_(f): −10.6 −9.5 −9.6 −7.6 −12.5−12.0 −11.5 −10.7 R_(g)Y: 6.5% 6.5% 6.5% 6% 7% 18% 19% 19.5%   a*_(g):−0.2 −0.7 −0.5 −0.4 0.7 3.2 3.7 2.9 b*_(g): −10.9 −10.0 −10.1 −9.4 −12.1−10.4 −9.9 −9.5 E_(n): 5.8% 6.0% 6.2% 6.6%   4.4%   2.7%  2.4%  2.6% 

The coated articles of Examples 1-8 were then thermally tempered (heattreated), and then were again measured monolithically after such HT andhad the following characteristics (HT, monolithic) (Ill. C, 2 degreeobserver). Note that glass side reflective ΔE* was 1.1 for Example 4,and that film side reflective ΔE* was 0.95 for Example 4. Also, notethat glass side reflective ΔE* was 2.1 for Example 5, and that film sidereflective ΔE* was 1.7 for Example 5. Also, note that glass sidereflective ΔE* was 2.2 for Example 8, and that film side reflective ΔE*was 3.7 for Example 8.

TABLE 8 Monolithic, Heat Treated (thermally tempered) Ex. 1 Ex. 2 Ex. 3Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 T_(vis) (or TY):  90%  90%  90%  90% 89% 79% 78% 77% a*_(t): −1.2 −1.2 −1.1 −1.1 −1.9 −3.2 −3.5 −3.4 b*_(t): 1.91.8 1.8 1.9 2.9 4.2 4.0 3.7 R_(f)Y:   5%   5%   6%   5% 6% 16% 17% 18%a*_(f): 0.4 −0.2 −0.3 −0.8 2.8 5.2 6.0 5.5 b*_(f): −10.8 −10.2 −9.9 −8.5−12.0 −10.1 −9.3 −7.6 R_(g)Y: 6.2% 6.2% 6.3% 5.9% 7% 18% 19% 20% a*_(g):0.5 0.0 −0.3 −0.1 2.7 4.4 3.6 4.7 b*_(g): −10.9 −10.4 −10.1 −9.8 −12.5−9.9 −9.4 −8.2 E_(n): 4.3% 4.5% 4.7% 4.8% 3.4%   1.9%  1.8%  1.9% 

The coated articles of Examples 1-8, before being thermally tempered,were put in IG window units on surface three as shown in FIG. 3, and theIG window units had the following characteristics (Ill. C, 2 degreeobserver). In the IG window units, for purposes of reference, the glasssubstrates 1 and 22 were clear and 3.8 mm thick, and the air gap in theIG window unit was 16 mm thick and filled with a mixture of air andargon gas.

TABLE 9 IG Window Unit, Annealed (non-HT) Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5Ex. 6 Ex. 7 Ex. 8 T_(vis) (or TY): 80% 80% 80% 80% 79% 71% 70% 69%a*_(t): −2.0 −2.0 −2.0 −2.1 −2.6 −3.7 −3.9 −3.6 b*_(t): 2.4 2.3 2.4 2.43.7 4.8 4.8 4.8 R_(f)Y: 13% 13% 13% 13% 14% 23% 24% 24% a*_(f): −0.2−0.5 −1.2 −1.1 −0.6 1.8 2.1 1.6 b*_(f): −5.8 −5.2 −5.9 −5.4 −7.2 −7.9−7.5 −7.4 R_(g)Y: 13% 13% 13% 13% 13% 21% 22% 22% a*_(g): −1.0 −1.3 −0.5−0.5 0.5 2.9 3.3 2.7 b*_(g): −6.5 −5.9 −5.2 −4.2 −6.9 −8.7 −8.5 −8.0U-Value: 1.2%  1.2%  1.2%  1.2%  1.2%  1.1%  1.0%  1.1% 

In certain example embodiments of this invention, there is provided acoated article including a coating supported by a glass substrate, thecoating comprising moving away from the glass substrate: a dielectriclayer comprising zirconium silicon oxynitride; a layer comprisingtitanium oxide; a layer comprising zinc stannate; a layer comprisingzinc oxide located over and directly contacting the layer comprisingzinc stannate; an infrared (IR) reflecting layer comprising silverlocated on the substrate over and directly contacting the layercomprising zinc oxide; and a layer comprising metal oxide located overat least the IR reflecting layer comprising silver; wherein the coatingcontains only one silver based IR reflecting layer; wherein the coatinghas a normal emissivity (E_(n)) of no greater than 7% (more preferablyno greater than 6%, possibly no greater than 4% or 5%), and measuredmonolithically the coated article has a visible transmission of at least75% (more preferably of at least 80%, and most preferably of at least86%).

In the coated article of the immediately preceding paragraph, the layercomprising zirconium silicon oxynitride may contain at least three timesas much nitrogen as oxygen, more preferably at least four times as muchnitrogen as oxygen, and most preferably at least five times as muchnitrogen as oxygen.

In the coated article of any of the preceding two paragraphs, a ratio ofZr/Si (atomic) may be from 0.30 to 0.47, more preferably from 0.35 to0.44, in the layer comprising zirconium silicon oxynitride.

In the coated article of any of the preceding three paragraphs, thelayer comprising titanium oxide may be located over and directlycontacting the layer comprising zirconium silicon oxynitride.

The coated article of any of the preceding four paragraphs may furthercomprise a layer comprising silicon nitride located between the glasssubstrate and the layer comprising zirconium silicon oxynitride.

In the coated article of any of the preceding five paragraphs, the layercomprising zirconium silicon oxynitride may be from about 40-250 (or20-250) Å thick, more preferably from about 50-100 Å thick.

In the coated article of any of the preceding six paragraphs, the layercomprising titanium oxide may be from about 15-150 Å thick, morepreferably from about 20-60 Å thick.

In the coated article of any of the preceding seven paragraphs, (a) thelayer comprising zinc stannate may be located over and directlycontacting the layer comprising titanium oxide, or (b) the coating mayfurther comprise, below said layer comprising zinc stannate and abovesaid layer comprising titanium oxide, another layer comprising zincstannate and another layer comprising zinc oxide, where said anotherlayer comprising zinc stannate directly contacts said layer comprisingtitanium oxide.

In the coated article of any of the preceding eight paragraphs, thelayer comprising metal oxide may comprise an oxide of Ni and/or Cr andmay be located directly over and contacting the IR reflecting layercomprising silver.

In the coated article of any of the preceding nine paragraphs, thecoating may further comprise one or more of: (i) at least one anotherlayer comprising zinc stannate and another layer comprising zinc oxidelocated over the IR reflecting layer comprising silver; (ii) a layercomprising silicon nitride located over the another layer comprisingzinc oxide; and/or (iii) a layer comprising tin oxide located betweenthe another layer comprising zinc oxide and the layer comprising siliconnitride.

The coated article of any of the preceding ten paragraphs may or may notbe heat treated (e.g., thermally tempered).

The coated article of any of the preceding eleven paragraphs may have,measured monolithically, a film side reflective ΔE* value of <=4.0 (morepreferably <=2.0, and most preferably <=1.5) due to heat treatment(e.g., thermal tempering).

The coated article of any of the preceding twelve paragraphs may have,measured monolithically, a glass side reflective ΔE* value of <=2.5(more preferably <=2.0, and most preferably <=1.5) due to heat treatment(e.g., thermal tempering).

An IG window unit may include the coated article of any of the precedingthirteen paragraphs, wherein the IG window unit has a U-value of nogreater than 1.4 (more preferably no greater than 1.1), the IG windowunit further comprising another glass substrate, and wherein the coatingmay be on surface three of the IG window unit.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1-34. (canceled)
 35. A coated article including a coating supported by aglass substrate, the coating comprising moving away from the glasssubstrate: a dielectric layer comprising zirconium silicon oxynitride; alayer comprising zinc stannate; a layer comprising zinc oxide locatedover and directly contacting the layer comprising zinc stannate; aninfrared (IR) reflecting layer comprising silver located on thesubstrate over and directly contacting the layer comprising zinc oxide;and a layer comprising metal oxide located over at least the IRreflecting layer comprising silver; wherein the coating contains onlyone silver based IR reflecting layer; wherein the coating has a normalemissivity (E_(n)) of no greater than 7%, and measured monolithicallythe coated article has a visible transmission of at least 75%.
 36. Thecoated article of claim 35, wherein the layer comprising zirconiumsilicon oxynitride contains at least three times as much nitrogen asoxygen.
 37. The coated article of claim 35, wherein the layer comprisingzirconium silicon oxynitride contains at least four times as muchnitrogen as oxygen.
 38. The coated article of claim 35, wherein a ratioof Zr/Si (atomic) is from 0.30 to 0.47 in the layer comprising zirconiumsilicon oxynitride.
 39. The coated article of claim 35, wherein a ratioof Zr/Si (atomic) is from 0.35 to 0.44 in the layer comprising zirconiumsilicon oxynitride.
 40. The coated article of claim 35, furthercomprising a layer comprising silicon nitride located between the glasssubstrate and the layer comprising zirconium silicon oxynitride.
 41. Thecoated article of claim 35, wherein the layer comprising zirconiumsilicon oxynitride is from about 20-250 Å thick.
 42. The coated articleof claim 35, wherein the layer comprising zirconium silicon oxynitrideis from about 50-100 Å thick.
 43. The coated article of claim 35,wherein the coating has a normal emissivity (E_(n)) of no greater than6%.
 44. The coated article of claim 35, wherein measured monolithicallythe coated article has a visible transmission of at least 86%.
 45. Thecoated article of claim 35, wherein the layer comprising metal oxidecomprises an oxide of Ni and/or Cr and is located directly over andcontacting the IR reflecting layer comprising silver.
 46. The coatedarticle of claim 35, further comprising another layer comprising zincstannate and another layer comprising zinc oxide located over the IRreflecting layer comprising silver.
 47. The coated article of claim 35,wherein the coated article is configured to have a film side reflectiveΔE* value of no greater than 4.0 due to heat treatment.
 48. The coatedarticle of claim 35, wherein the coated article is configured to have afilm side reflective ΔE* value of no greater than 2.0 due to heattreatment comprising thermal tempering.
 49. The coated article of claim35, wherein the coated article is configured to have a glass sidereflective ΔE* value of no greater than 2.5 due to heat treatmentcomprising thermal tempering.
 50. The coated article of claim 35,wherein the coated article is configured to have a glass side reflectiveΔE* value of no greater than 2.0 due to heat treatment comprisingthermal tempering.
 51. An IG window unit comprising the coated articleof claim 35, wherein the IG window unit has a U-value of no greater than1.4, the IG window unit further comprising another glass substrate, andwherein the coating is on surface three of the IG window unit.
 52. An IGwindow unit comprising the coated article of claim 35, wherein the IGwindow unit has a U-value of no greater than 1.1, the IG window unitfurther comprising another glass substrate, and wherein the coating ison surface three of the IG window unit.
 53. An IG window unitcomprising: first and second glass substrates with a gap therebetween; acoating supported by the second glass substrate and facing the gap, thesecond glass substrate to be located closer to a building interior thanis the first glass substrate, the coating comprising moving away fromthe second glass substrate: a dielectric layer comprising zirconiumsilicon oxynitride; a layer comprising zinc stannate; a layer comprisingzinc oxide located over and directly contacting the layer comprisingzinc stannate; an infrared (IR) reflecting layer comprising silverlocated on the substrate over and directly contacting the layercomprising zinc oxide; and a layer comprising metal oxide located overat least the IR reflecting layer comprising silver; wherein the coatingcontains only one silver based IR reflecting layer; wherein the coatinghas a normal emissivity (E_(n)) of no greater than 7%; wherein the IGwindow unit has a visible transmission of at least 70% and a U-value ofno greater than 1.4.
 54. A coated article including a coating supportedby a glass substrate, the coating comprising moving away from the glasssubstrate: a dielectric layer comprising zirconium silicon oxynitride; alayer comprising zinc stannate; a layer comprising zinc oxide locatedover and directly contacting the layer comprising zinc stannate; aninfrared (IR) reflecting layer comprising silver located on thesubstrate over and directly contacting the layer comprising zinc oxide;and a layer comprising metal oxide located over at least the IRreflecting layer comprising silver; and wherein a ratio of Zr/Si(atomic) is from 0.30 to 0.47 in the layer comprising zirconium siliconoxynitride.